/// <summary>
/// Read some of a file and return as a string.
/// </summary>
/// <param name="hash">Hash to look up.</param>
/// <param name="sampleSize">Amount of content to return.</param>
/// <returns>Byte array representing the object.</returns>
public static string Read(Span <byte> hash, uint sampleSize)
{
if (!IsValid(hash))
{
throw new SignatureException("Hash mismatch");
}
var fullPath = NitPath.GetFullObjectPath(hash);
if (!File.Exists(fullPath))
{
// already exists, don't bother
return(null);
}
var buffer = new char[sampleSize];
var bufferSpan = (Span <char>)buffer;
using (var sr = new StreamReader(fullPath))
{
sr.ReadBlock(bufferSpan);
}
return(bufferSpan.ToString());
}
/// <summary>
/// Check if file is valid.
/// </summary>
/// <param name="hash">The file's hash.</param>
/// <returns>If the hash still matches.</returns>
public static bool IsValid(Span <byte> hash)
{
var fullPath = NitPath.GetFullObjectPath(hash);
var hashCheck = Hash.HashFile(fullPath);
return(hash.SequenceEqual(hashCheck));
}
/// <summary>
/// Write a blob to the object index.
/// </summary>
/// <param name="blob">Blob to write.</param>
/// <returns>Hashed blob.</returns>
public static Span <byte> Write(Span <byte> blob)
{
var hash = Hash.HashObject(blob);
var blobPath = NitPath.GetFullObjectPath(hash);
// ensure folders exist
var blobFolder = NitPath.GetObjectDirectoryPath(hash);
Directory.CreateDirectory(blobFolder);
File.WriteAllBytes(blobPath, blob.ToArray());
return(hash);
}
/// <summary>
/// Read the entry for a given hash.
/// </summary>
/// <param name="hash">Hash to look up.</param>
/// <returns>Byte array representing the object.</returns>
public static Span <byte> Read(Span <byte> hash)
{
if (!IsValid(hash))
{
throw new SignatureException("Hash mismatch");
}
var fullPath = NitPath.GetFullObjectPath(hash);
if (!File.Exists(fullPath))
{
// already exists, don't bother
return(null);
}
return(File.ReadAllBytes(fullPath));
}
/// <summary>
/// Copy source file to object index.
/// </summary>
/// <param name="targetPath">Path to write blob.</param>
/// <returns>Hash of blob written.</returns>
public static Span <byte> Write(string targetPath)
{
if (!File.Exists(targetPath))
{
throw new ArgumentException("Target does not exist.");
}
var hash = Hash.HashFile(targetPath);
var fullPath = NitPath.GetFullObjectPath(hash);
var dirPath = NitPath.GetObjectDirectoryPath(hash);
if (File.Exists(fullPath))
{
// already exists, don't bother
return(hash);
}
// ensure the folders exist
Directory.CreateDirectory(dirPath);
// copy the file, using the hex hash as the filename
File.Copy(targetPath, fullPath);
return(hash);
}